﻿using System;
using System.Windows.Data;
using System.Globalization;
using System.Windows;
using System.Windows.Input;
using System.Windows.Markup;

// Taken from the Mvvm helpers of Mark Smith, http://www.julmar.com/blog/mark/2009/04/17/WPFMVVMHelperLibraryWPFMVVMTestability.aspx
// original namespace is JulMar.Windows.Converters
namespace Elca.MvvmHelpers {
    /// <summary>
    /// This converter reverses a Boolean value (True == False, False == True).
    /// </summary>
#if WPF
    [ValueConversion(typeof(ICommand), typeof(bool))]
#endif
    public class CommandToVisibilityConverter :
#if WPF
        MarkupExtension,
#endif
        IValueConverter {
        /// <summary>
        /// Converts a value. 
        /// </summary>
        /// <returns>
        /// A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">The value produced by the binding source.</param><param name="targetType">The type of the binding target property.</param><param name="parameter">The converter parameter to use.</param><param name="culture">The culture to use in the converter.</param>
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture) {

            ICommand cmd = value as ICommand;
            if (cmd != null) {
                return cmd.CanExecute(parameter) ? Visibility.Visible : Visibility.Collapsed;
            }

            return Visibility.Collapsed;
        }

        /// <summary>
        /// Converts a value. 
        /// </summary>
        /// <returns>
        /// A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">The value that is produced by the binding target.</param><param name="targetType">The type to convert to.</param><param name="parameter">The converter parameter to use.</param><param name="culture">The culture to use in the converter.</param>
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) {
            throw new NotSupportedException();
        }

        /// <summary>
        /// Returns the converter
        /// </summary>
        /// <param name="serviceProvider"></param>
        /// <returns></returns>
        public override object ProvideValue(IServiceProvider serviceProvider) {
            return new CommandToVisibilityConverter();
        }
    }
}